He quickly rejected the Yaojiang school of Wang Yangming, favouring the strong moral dichotomy of earlier Song philosophers such as Zhu Xi.
[3] Together with his brother and his student Gao Panlong he rebuilt the Donglin ("East Forest") Academy in 1604, in the town of Wuxi.
[4] The Donglin Charter was based on Zhu Xi's Articles of the White Deer Grotto, and incorporated quotations from a number of Confucian classics.
Gu required prospective entrants to have four key qualities, which he called the Four Essentials: students had to consider their fundamental nature, show firm resolve, respect the Classics and scrutinise their own motivation.
[5] Gu's Academy quickly attracted a large student base, and became a rallying point for dissent and criticism of the government, in the form of the Donglin movement.